Von Schweikert VR4, VR4.5 upgrades?? anyone

Has anyone done the Von Schweikert VR4 or VR 4.5 upgrades?

I have a pair of Vortex Screens which are similiar to the VR4's. The price with shipping is around $3k.

The vortex screens seem to have just a little shrillness on the very top end on some material (source dependant), but otherwise are an excellent speaker with great imaging, no cabinet colorations, and great tonal balance and trasparency. Every time I upgrade something, these speakers hold their own, so now I'm wondering if they are the logical next step in the upgrading bug and pursuit of natural musical reproduction.

I would be interested to here your comments on the Vr4 or VR4.5 speaker upgrades.

thanks

Tom